Hannover 2016 – scientific programme
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P: Fachverband Plasmaphysik
P 20: Poster Session- Low Temperature Plasmas
P 20.14: Poster
Wednesday, March 2, 2016, 16:30–19:00, Empore Lichthof
Fast plasma potential measurements within a reconnecting current sheet via laser-heated emissive probes — •Adrian von Stechow1, Olaf Grulke1, and Thomas Klinger1,2 — 1Max-Planck-Institut für Plasmaphysik, Greifswald — 2Ernst Moritz Arndt-Universität Greifswald
During driven magnetic reconnection, a current sheet forms in the plasma between opposed field lines in response to externally applied, time-dependent magnetic fields. In contrast to paradigmatic periodic 2D reconnection models, electrostatic fields should be present not only perpendicular to the current sheet, but also parallel to it due to the axial boundary conditions present in our linear, open field line geometry. Previous results from the linear reconnection experiment VINETA.II suggest that substantial time-dependent electrostatic fields must be present in order to account for the observed current sheet structure and its temporal evolution.
Emissive probes provide a means of directly measuring the plasma potential, providing the electron emission by the probe roughly matches the electron saturation current. The electronics involved in their heating schemes are often plagued by high stray capacitance which limits their time response. In order to capture the fast temporal dynamics present in our experiment, our emissive probe is heated externally by a high-power infrared laser. This contribution presents spatio-temporal plasma potential and electric field profiles recorded by this novel, freely positionable probe system that give further insight into the complex 3D dynamics of our reconnecting system.